First-principles calculations of the atomic structure of the In-induced Si(001)-(4X3) reconstruction

Using first-principles total-energy calculations, we have studied the atomic structure of the indium-induced Si(001)-(4x3) reconstruction. Three different models were considered. Our results indicate that the pyramidlike reconstruction proposed by Bunk et al. [Appl. Surf. Sci. 123/124, 104 (1998)] is more stable than the modulated (4x1) model of Zotov et al. [Phys. Rev. B 57, 12 492 (1998)], and the structure with seven In atoms/cell proposed by Saranin et al. [Phys. Rev. B 60, 14 372 (1999)]. Simulated scanning tunneling microscopy (STM) images based on the model of Bunk et al. are in better agreement with STM experiments than those based on the model of Zotov et al. An optimized structure with seven In atoms/cell is not compatible with STM experiments. These results strongly support pyramidlike structure of Bunk et nl. to explain the Si(001)-(4x3)-In reconstruction.